This project is designed to develop a procedure for assessment of spoken language dysfunction in 9-13 year old dyslexic boys. Although dyslexia is defined as a disorder of reading, there is growing evidence that the largest subcategory of dyslexics exhibit a more generalized language dysfunction, of which their reading problem is only one manifestation. We have under study a highly screened population of "pure" dyslexics who exhibit no deficits in intelligence, sensory function, or neurological status. Extensive psychometric and physiological data are available on this population. We also have available for each child an eight-minute sample of spontaneous speech recorded during an EEG session. A matched control group of normal readers is also participating in the study, and the same data and speech samples are available. In the current application, we propose to analyze these speech samples in order to determine which aspects of spoken language reflect the language disorder which characterizes the dyslexic population. A number of potential indices available from studies on other populations are available, and will be evaluated for their utility in assessment of dyslexics. These indices include measurements of fluency; grammatical structures; nonstandard usage, syntax, and grammar; vocabulary measured by diversity and frequency; and coherence. Our current population consists of 35 dyslexics and 35 controls; an additional 25 and 25 are currently being screened for a replication study. All measures will be initially evaluated on the data from the first set of 35/35; the measures chosen will be cross-validated using the data from the second 25/25, which will not be analyzed until the first cohort is completed. The validated results should provide valuable information on the nature of spoken language dysfunction in dyslexics, and could be the basis for subsequent development of a standardized assessment tool which is not currently available for this population.